The major objective of this proposal is to participate in the overall activities of the Eastern Cooperative Oncology Group (ECOG). The aims of the group are defined in the group chairman's application and are summarized here. They are: 1. The early evaluation of potential antitumor drugs, including toxicology, clinical pharmacology, and evaluation of therapeutic efficacy. 2. The development of new methods of testing antitumor drugs in humans. 3. A continuing concern with experimental design and human pharmacology to be used for the application of animal screening of antitumor compounds to the selection of effective chemotherapeutic drugs. 4. To improve knowledge of the biology and biochemistry of malignant disease. 5. To enhance the collation of the clinical data for application to biostatistical programs. 6. The Principal Investigator is an active member of the surgical subcommittee and along with Dr. Ed Mansour will be co-chairman of the adjuvant colo-rectal protocol. 7. Continue the study of a new anti-estrogen (Tamoxifen) in the treatment of metastatic breast cancer. 8. A phase II study is being performed in State D Prostatic carcinoma using Hydroxyurea, with over 30 patients treated. Hydroxyurea is a very active drug with measurable prolonged tumor responses including recalcification of bone metastasis. BIBLIOGRAPHIC REFERENCES: Lerner, H., Malloy, T. Hydroxyurea in State D Carcinoma of the Prostrate: A Pilot Study. The Journal of Urology, Volume 114, September, 1975, 425-429. Lerner, H. J. Colorectal Cancer--Prognostic Signs in Local Disease. Journal of Surgical Oncology, 7: 395-402, 1975.